Missing set-xml-id in xi:include?

Hi,

just read Jirka's "DocBook Transclusion"[1] document. In Appendix A. "Usin=
g
XInclude 1.1 features for your content" there is Example A.3 "Using set-xm=
l-id
to remove the top-level ID during transclusion".

The set-xml-id attribute is mentioned in the XInclude 1.1 specification[2]=
.

However, when you search for set-xml-id in DocBook 5.2CR3 it's missing. Th=
is
attribute isn't available in docbookxi.rn{c,g} at all. Is this an omission=
?

With the current implementation, the above mentioned example wouldn't be
possible and would raise a validation error. :)


=2D---- Reference
[1] https://documents.docbook.org/transclusion
[2] https://www.w3.org/TR/xinclude-11/#include_element

=2D-
Gru=C3=9F/Regards
   Thomas Schraitle